This study assesses the differential performance effects of learning mechanisms in alliance portfolios. Investigating two distinct types of learning mechanisms (i.e. integrating and institutionalizing mechanisms), the results show that different learning mechanisms have difrerent performance effects at distinct levels of alliance experience. The results are based on a detailed survey among alliance managers and vice-presidents of 192 firms reporting on over 3400 alliances formed over the period 1997-2001. The main lesson from this study is that firms can deliberately develop their alliance capabilities by using integrating mechanisms to transfer prior experiences.